JP2023088083A - Earth retaining wall removal method - Google Patents

Abstract

To provide an earth retaining wall removal method that facilitates installation and suppresses ground subsidence.SOLUTION: An earth retaining wall removal method according to an embodiment comprises steps of driving an earth retaining wall 1 into a ground B, excavating a ground B located on one side of the earth retaining wall 1 in plan view, constructing a skeleton T in a space formed by excavation, filling a gap between the earth retaining wall 1 and the skeleton T with a filling material 10 to harden over time, and pulling out the earth retaining wall 1 from the ground B before the filling material 10 hardens.SELECTED DRAWING: Figure 6

Description

The present disclosure relates to an earth retaining wall removal method for removing an earth retaining wall.

Various methods are conventionally known for removing earth retaining walls. Japanese Patent No. 3940735 describes an earth retaining method. In the earth retaining method, sheet piles are driven into the ground. A hardener injection tube is attached to the sheet pile by attachment means and clasps. The hardener injection pipe is attached along the longitudinal direction of the sheet pile. An ejection port through which the curing agent is ejected is formed at the tip of the curing agent injection tube.

When the sheet pile is driven into the ground, the hardening agent injection pipe also goes into the ground, so that the hardening agent can be injected into the ground from the hardening agent injection pipe. A plug for opening and closing the spout, and biasing means for urging the plug to close the spout are built into the tip of the curing agent injection tube. When the hardening agent is injected into the ground, the plug is moved against the biasing force of the biasing means by the injection pressure, and the spout is opened into the ground, whereby the hardening agent is jetted out to the ground.

Japanese Unexamined Patent Application Publication No. 2016-148137 describes a method for removing an earth retaining portion. In the earth retaining part removal method, the surroundings of the earth retaining part, which is a steel sheet pile with a hat-shaped cross section, are excavated to form a recess in the ground surface around the earth retaining part, and the earth retaining part is removed with a crane while the recess is filled with fluidized treated soil. Pull out. When the earth retaining member is pulled out, a gap communicating with the recess is formed between the earth retaining member and the ground, and the fluidized soil flows into the gap from the recess. In this way, the fluidized soil flows into the gaps formed when the earth retaining member is pulled out, thereby reducing the impact on the surrounding ground and the like.

Japanese Patent No. 3940735 JP 2016-148137 A

In the earth retaining method described above, since it is necessary to attach the hardener injection pipe to the sheet pile in advance, there may arise a problem that the installation cannot be easily performed. In addition, in the method of pouring the fluidized soil into the gap between the retaining member and the ground by pulling out the retaining member while filling the fluidized soil in the recess formed in the ground surface, the fluidized treated soil is sufficiently filled in the gap. It may not fill. Specifically, when the earth retaining member is pulled out, first, a gap is formed between the lower end of the earth retaining member and the ground.

However, since the voids do not communicate with the recesses located on the ground surface, the voids are not filled with the fluidized soil. Therefore, in the above-described earth retaining portion removing method, since the fluidized soil is not sufficiently filled into the voids in the ground, there is a concern that the voids may remain. In this case, there is a concern that the ground will subside due to voids left inside. That is, since the gap does not communicate with the concave portion located on the ground surface, the gap is filled with the fluidized soil only after the earth retaining member is completely pulled out. In this case, before the fluidized soil is filled, there is a concern that the surrounding ground will collapse into the gap, causing the ground to subside.

An object of the present disclosure is to provide an earth retaining wall removal method that facilitates installation and suppresses subsidence of the ground.

A method for removing an earth retaining wall according to the present disclosure includes the steps of driving an earth retaining wall into the ground, excavating the ground located on one side of the earth retaining wall in a plan view, and constructing a frame in the space formed by excavation. filling a gap between the earth retaining wall and the skeleton with a filling material that hardens with the lapse of time; and pulling out the earth retaining wall from the ground before the filling material hardens.

In this retaining wall removal method, a framework is constructed in a space formed by excavating the ground located on one side of the retaining wall, and then the retaining wall is pulled out from the ground. After the building frame is constructed, it is filled with a filling material that hardens over time, and the retaining wall is pulled out before the filling material hardens. Since the earth retaining wall is pulled out from the ground before the filling material hardens, the filling material can be densely filled in the gaps after the earth retaining wall is pulled out together with the earth retaining wall being pulled out. By densely filling the gap with the filling material, it is possible to prevent the surrounding ground of the retaining wall from collapsing into the gap. Therefore, it is possible to suppress subsidence of the ground after the retaining wall is pulled out. In addition, since it is only necessary to fill the space between the retaining wall and the frame with the filler and pull out the retaining wall, it is possible to eliminate the need for work such as attaching pipes to the retaining wall in advance. Therefore, it is possible to easily install equipment for suppressing subsidence of the ground.

The earth retaining wall removal method may comprise, after the step of constructing the skeleton, a step of installing a formwork between the earth retaining wall and the skeleton, and a step of backfilling between the formwork and the skeleton. good. In the step of filling the filling material, the filling material may be filled between the retaining wall and the formwork after the step of backfilling. The retaining wall removal method may further include a step of pulling out the formwork from the ground after the step of filling the filler. In this case, a formwork is placed between the earth retaining wall and the frame, and a filling material is filled between the earth retaining wall and the formwork. Therefore, the amount of filler can be reduced compared to the case where the filler is filled between the earth retaining wall and the skeleton. As a result, the amount of filler used can be reduced and the cost of the filler can be reduced.

The step of installing the formwork may include interposing a camber between the earth retaining wall and the formwork. Withdrawing the formwork may include withdrawing the camber from the filler. In this case, since the camber is arranged between the earth retaining wall and the formwork, the formwork can be easily pulled out.

The camber may be connected via a hinge to the surface of the formwork facing the retaining wall. In the step of pulling out the camber, the camber may be pulled out together with the mold in a rotatable state via a hinge. In this case, since the camber is connected to the formwork, the camber can be pulled out together with the formwork. Therefore, the formwork and camber can be easily pulled out. Furthermore, the camber is pivotally connected to the formwork via a hinge. Therefore, when the formwork is pulled out, the camber can be rotated with respect to the formwork, so that it is possible to prevent the camber from being caught and difficult to come off when the formwork is pulled out. Therefore, the formwork and camber can be pulled out more easily.

Advantageous Effects of Invention According to the present disclosure, installation can be easily performed and ground subsidence can be suppressed.

1(a) is a vertical cross-sectional view showing a site to which an earth retaining wall removing method according to an embodiment is applied. FIG. (b) is a cross-sectional view taken along the line AA of FIG. 1(a). (a) is a vertical cross-sectional view showing a state in which an earth retaining wall and a skeleton are constructed at the site of FIG. 1(a). (b) is a cross-sectional view taken along line BB of FIG. 2(a). (a) is a vertical cross-sectional view showing a state in which a formwork and a camber are installed at the site of FIG. 2(a). 3(b) is a sectional view taken along line CC of FIG. 3(a). (a) is a side view showing an enlarged camber. (b) is a side view showing a camber according to a modification. (a) is a vertical cross-sectional view showing a state in which backfilling has been performed between the frame and formwork at the site of FIG. 4(a). (b) is a cross-sectional view taken along line DD of FIG. 5(a). (a) is a vertical cross-sectional view showing a state in which a filler is filled at the site of FIG. 5(a). (b) is a cross-sectional view taken along line EE of FIG. 6(a). FIG. 4 is a side view schematically showing a camber that rotates when the mold is pulled out. It is a side view which shows typically the camber which rotates at the time of extraction of an earth retaining wall in a modification.

An embodiment of the retaining wall removal method according to the present disclosure will be described below with reference to the drawings. In the description of the drawings, the same reference numerals are given to the same or corresponding elements, and overlapping descriptions are omitted as appropriate. Also, the drawings may be partially simplified or exaggerated to facilitate understanding, and dimensions, ratios, angles, and the like are not limited to those described in the drawings.

FIG. 1(a) is a longitudinal sectional view showing a site S to which the retaining wall removing method according to the present embodiment is applied. FIG. 1(b) is a sectional view taken along line AA of FIG. 1(a). As shown in FIGS. 1(a) and 1(b), at the site S, for example, a skeleton T, which is an underground skeleton, is constructed. A layer K formed by curing a filling material 10, which will be described later, is provided around the skeleton T in plan view. The layer K has a flat first surface K1 facing the skeleton T side and a wave-shaped second surface K2 facing away from the skeleton T side.

For example, the skeleton T is an underground structure constructed underground and is buried in the ground B. As an example, the skeleton T includes a subway platform. In this case, the skeleton T has a space T1 inside the skeleton T through which the railroad passes. However, the skeleton T need not be a subway platform and can include various structures.

The filler 10 is not hardened at the time of filling and has fluidity. The filler 10 hardens over time. For example, the filler 10 is fluidized soil. Fluidized soil includes cement, soil (construction soil as an example) and water. The fluidized soil may be soil mixed with water and a solidifying material.

For example, at the site S, a skeleton T is constructed in an underground space formed by an earth retaining wall 1 (see FIG. 2), which will be described later. pulled out from However, if the earth retaining wall 1 is simply pulled out, a gap corresponding to the thickness of the earth retaining wall 1 will be formed in the ground B. If the gap remains formed in the ground B, the ground B may collapse into the gap, causing the ground B to subside. I don't like it. Therefore, there is a demand for a construction method that does not form voids in the ground B after the earth retaining wall 1 is pulled out.

The retaining wall 1 is used when constructing the skeleton T, and is removed after the skeleton T is constructed. As an example, the retaining wall 1 has a thickness of 15 mm. For example, the earth retaining wall 1 is a leased material and is expensive to use, so it is desirable to remove it from the ground B. In addition, if the earth retaining wall 1 is left on the ground B for a long period of time, it may impede the flow of groundwater.

A method for removing an earth retaining wall according to this embodiment will be described below. As shown in FIGS. 2(a) and 2(b), first, an earth retaining wall 1 is driven into the ground B (step of driving an earth retaining wall). The retaining wall 1 is composed of, for example, a plurality of steel sheet piles 1b. The steel sheet pile 1b has a trapezoidal shape in a cross section taken along a plane perpendicular to the longitudinal direction of the steel sheet pile 1b. In the cross section, the steel sheet pile 1b has a bottom portion 1c and a pair of leg portions 1d obliquely extending from both ends of the bottom portion 1c.

A connection portion 1f to which another steel sheet pile 1b is connected is provided at the end portion of the leg portion 1d opposite to the bottom portion 1c. A plurality of steel sheet piles 1b are connected to each other by connecting a pair of connecting portions 1f to each other. As an example, the connection portion 1f is U-shaped, and the pair of steel sheet piles 1b are connected by fitting the pair of U-shaped connection portions 1f to each other. The plurality of steel sheet piles 1b are connected to each other so as to form a wavy shape in plan view. In plan view, the earth retaining wall 1 is formed, for example, to have a rectangular frame shape.

After the earth retaining wall 1 is driven into the ground B, the ground B located on one side of the earth retaining wall 1 in plan view is excavated (step of excavating the ground). As an example, the inner portion of the frame-shaped retaining wall 1 in plan view is excavated. By excavating the ground B, a space C for constructing the skeleton T is formed below the ground surface U. After the space C is formed, the framework T is constructed by setting the formwork and placing concrete, etc. (step of constructing the framework).

Then, as shown in FIGS. 3(a) and 3(b), the formwork 2 is installed between the frame T and the earth retaining wall 1 (step of installing the formwork). As an example, the formwork 2 is made of wood. The formwork 2 has a first surface 2b facing the skeleton T side and a second surface 2c facing the retaining wall 1 side. For example, the coefficient of friction of the first surface 2b is smaller than that of the second surface 2c. As a result, the formwork 2 can be smoothly pulled out from the backfilling soil Y, which will be described later.

For example, the support member 3 is interposed between the mold 2 and the skeleton T (step of interposing the support member). The support member 3 is provided to prevent the formwork 2 from overturning toward the skeleton T side. As an example, a plurality of support members 3 are arranged so as to line up along the vertical direction. The plurality of support members 3 are removed one by one from the support members 3 located below, for example, as the backfill soil Y is backfilled.

A camber 5 is interposed between the formwork 2 and the retaining wall 1 (step of interposing the camber). A camber 5 is interposed between the formwork 2 and the earth retaining wall 1. - 特許庁By securing the interval W, the camber 5 enables the filling material 10 to be filled with a small number of times when the filling material 10 is placed. That is, when the camber 5 is provided, it becomes possible to fill a wide range with the filler 10 at once. The camber 5 is made of wood, for example. FIG. 4A is an enlarged side view of the camber 5. FIG.

As shown in FIG. 4( a ), the camber 5 has an upper surface 5 b facing vertically upward, a lower surface 5 c facing vertically downward, a first side surface 5 d facing the formwork 2 , and an earth retaining wall 1 . and a second side surface 5f. The camber 5 is rotatably supported by the formwork 2 via hinges 6, for example. As an example, the hinge 6 is fixed between the first side surface 5d and the lower surface 5c (lower end of the first side surface 5d) and the formwork 2, and the camber 5 is rotatable around the hinge 6. there is

For example, the vertical length of the second side surface 5f is shorter than the vertical length of the first side surface 5d. As an example, the camber 5 has an inclined surface 5g located between the upper surface 5b and the second side surface 5f. An inclined surface 5g is formed between the upper surface 5b and the second side surface 5f, and the vertical length of the second side surface 5f is shorter than the length of the first side surface 5d. 2 can be easily pulled up.

An exemplary camber 5 has been described above. However, the camber interposed between the formwork 2 and the earth retaining wall 1 may be a configuration other than the camber 5, and may be, for example, a camber 5A shown in FIG. 4(b). The camber 5A has a columnar portion 5h that abuts on the formwork 2 and an inclined portion 5j that abuts on the retaining wall 1. As shown in FIG. For example, the inclined portion 5j has a truncated cone shape.

As shown in FIGS. 3( a ) and 3 ( b ), the camber 5 is interposed between the bottom portion 1 c of the retaining wall 1 protruding toward the formwork 2 and the formwork 2 . As a result, a gap W corresponding to the length of the camber 5 is formed between the retaining wall 1 and the formwork 2 . For example, a plurality of cambers 5 are arranged so as to line up along the vertical direction.

Then, backfilling is performed between the formwork 2 and the skeleton T (step of backfilling). At this time, the space C between the formwork 2 and the skeleton T is filled with backfilling soil Y from below. As described above, the support member 3 is removed while the backfill soil Y is being filled. As shown in FIGS. 5(a) and 5(b), for example, backfilling with backfilling soil Y is performed until the backfilling soil Y reaches the ground surface U. As shown in FIG. Even in this state, a state in which a space C is formed between the retaining wall 1 and the formwork 2 by the plurality of cambers 5 is maintained.

After that, as shown in FIGS. 6(a) and 6(b), the space C between the retaining wall 1 and the formwork 2 is filled with the filler 10. Then, as shown in FIGS. At this point, the filler 10 is not hardened and has fluidity. At this time, a filler 10 is filled between the plurality of steel sheet piles 1b and the formwork 2, and the camber 5 is buried in the filler 10. - 特許庁More specifically, the filling material 10 is filled between the plurality of bottom portions 1 c and the plurality of leg portions 1 d and the second surface 2 c of the formwork 2 . The filling material 10 is filled from the bottom surface of the space C to a height equal to or higher than the height of the ground surface U.

After filling the space C with the filler 10 as described above and before the filler 10 hardens, the formwork 2 is pulled out from the ground B (step of pulling out the formwork). As described above, the camber 5 is rotatably attached to the second surface 2c of the formwork 2 via the hinge 6. Therefore, as shown in FIG. It is withdrawn from the filler 10 (step of withdrawing the camber). At this time, the camber 5 is pulled out from the filling material 10 together with the formwork 2 while rotating obliquely downward around the hinge 6 located at the lower end of the first side surface 5d.

Then, the earth retaining wall 1 is pulled out from the ground B before the filling material 10 hardens (step of pulling out the earth retaining wall). The retaining wall 1 is pulled out by, for example, holding the retaining wall 1 and pulling it up from the ground B with a hydraulic press-fit extractor. The above-described drawing of the formwork 2 may be performed by this hydraulic press-fit drawing machine. For example, the formwork 2 is pulled out before the retaining wall 1 is pulled out. However, the drawing of the formwork 2 may be performed after the drawing of the earth retaining wall 1, and the order of the process of drawing out the formwork and the process of drawing out the earth retaining wall can be changed as appropriate.

When the earth retaining wall 1 is pulled out, the filler 10 enters from the side into the space of the ground B formed by the earth retaining wall 1 being pulled out, and the space is filled with the filler 10.例文帳に追加As described above, the earth retaining wall 1 is pulled out and the space is densely filled with the filling material 10. After the filling material 10 has hardened after a certain period of time has elapsed, as shown in FIGS. completes a series of steps.

Next, functions and effects obtained from the method for removing an earth retaining wall according to this embodiment will be described. As shown in FIGS. 3(a), 3(b), 6(a) and 6(b), in the earth retaining wall removing method according to this embodiment, the A skeleton T is constructed in a space C formed by excavating the ground B, and then the earth retaining wall 1 is pulled out from the ground B. After the skeleton T is constructed, the filling material 10 that hardens over time is filled, and the earth retaining wall 1 is pulled out before the filling material 10 hardens. Since the earth retaining wall 1 is pulled out from the ground B before the filling material 10 hardens, the filling material 10 can be densely filled in the gap of the earth retaining wall 1 as the earth retaining wall 1 is pulled out.

By densely filling the ground B with the filler 10, it is possible to prevent the ground B from being left with voids. Therefore, it is possible to suppress subsidence of the ground B after the earth retaining wall 1 is pulled out. In addition, since it is only necessary to fill the space between the retaining wall 1 and the frame T with the filling material 10 and pull out the retaining wall 1, work such as attaching pipes to the retaining wall 1 in advance can be eliminated. Therefore, it is possible to easily install equipment for suppressing subsidence of the ground B, or the like.

The earth retaining wall removing method according to the present embodiment includes, after the step of constructing the skeleton T, the step of installing the formwork 2 between the earth retaining wall 1 and the skeleton T, and the step of installing the formwork 2 between the formwork 2 and the skeleton T. and backfilling. In the step of filling the filling material 10, the filling material 10 is filled between the earth retaining wall 1 and the formwork 2 after the step of backfilling. The retaining wall removing method according to this embodiment further includes a step of pulling out the formwork 2 from the ground B after the step of filling the filler 10 .

Therefore, the formwork 2 is arranged between the earth retaining wall 1 and the frame T, and the filling material 10 is filled between the earth retaining wall 1 and the formwork 2 . Therefore, compared with the case where the filler 10 is filled between the earth retaining wall 1 and the skeleton T, the amount of the filler 10 can be reduced. As a result, the amount of the filler 10 used can be reduced and the cost of the filler 10 can be reduced.

As described above, when the filler 10 is fluidized soil, the cost of fluidized soil is generally high, resulting in an increase in cost. However, when the formwork 2 is arranged as in the present embodiment and the filler 10 is filled between the formwork 2 and the retaining wall 1, the amount of the filler 10 can be minimized. . Therefore, the cost of the filling material 10 can be kept low.

In the present embodiment, the step of installing the formwork 2 includes the step of interposing the camber 5 between the earth retaining wall 1 and the formwork 2, and the step of pulling out the formwork 2 includes the step of removing the camber 5 from the filler 10. including the step of pulling out the Therefore, since the camber 5 is arranged between the retaining wall 1 and the formwork 2, the formwork 2 can be easily pulled out.

In the method for removing the earth retaining wall according to this embodiment, as shown in FIGS. 4A and 7, before the earth retaining wall 1 is pulled out, the formwork 2 with the camber 5 abuts on the earth retaining wall 1. is used. Since the camber 5 is attached to the mold 2 in this way, the space W can be secured, and the filling material 10 can be filled with a small number of times when the filling material 10 is placed.

In this embodiment, the camber 5 is connected to the second surface 2c of the formwork 2 facing the earth retaining wall 1 via a hinge 6. In the step of pulling out the camber 5, the camber 5 is hinged together with the formwork 2. 6 withdrawn in a rotatable state. Therefore, since the camber 5 is connected to the formwork 2, the camber 5 can be pulled out together with the formwork 2. - 特許庁

Therefore, the mold 2 and the camber 5 can be easily pulled out. Further, the camber 5 is rotatably connected to the formwork 2 via hinges 6 . Therefore, since the camber 5 can be rotated with respect to the mold 2 when the mold 2 is pulled out, it is possible to prevent the camber 5 from being caught and difficult to come off when the mold 2 is pulled out. Therefore, the mold 2 and the camber 5 can be pulled out more easily.

The embodiment of the retaining wall removal method according to the present disclosure has been described above. However, the present invention is not limited to the above-described embodiments, and can be modified as appropriate without changing the gist of the claims. That is, the content and order of the steps of the retaining wall removal method according to the present disclosure can be changed as appropriate within the scope of the above gist.

In the embodiment described above, an example in which the filler 10 is fluidized soil has been described. However, the filler may be something other than fluidized soil, such as mortar. In the embodiment described above, an example in which the camber 5 is attached to the formwork 2 has been described. However, the camber may also be attached to the retaining wall.

FIG. 8 shows an example in which the camber 15 is attached to the earth retaining wall 11 via hinges 16 . As shown in FIG. 8, the camber 15 includes an upper surface 15b facing vertically upward, a lower surface 15c facing vertically downward, a first side surface 15d facing the retaining wall 11, and a second side surface facing the formwork 12. 15f, and the hinge 16 is fixed between the first side surface 15d and the lower surface 15c and to the retaining wall 11. As shown in FIG. In the earth retaining wall 11 to which the camber 15 is attached via the hinge 16, the earth retaining wall 11 and the camber 15 can be easily pulled out, similarly to the above-described formwork 2.

In the embodiment described above, an example in which the formwork 2 and the camber 5 are arranged has been described. However, it is also possible to omit at least one of the formwork 2 and the camber 5 . For example, when the formwork 2 is omitted, after constructing the skeleton T in the space C, the filler 10 is filled between the earth retaining wall 1 and the skeleton T, and the earth retaining wall is filled before the filler 10 hardens. 1 is pulled out. Even in this case, the same effect as the earth retaining wall removal method according to the embodiment can be obtained.

In the above-described embodiment, the earth retaining wall 1, which is the steel sheet pile 1b, has been described. However, the earth retaining wall may be something other than the steel sheet pile 1b, and may be a main pile, for example. Further, in the above-described embodiment, an example in which the earth retaining wall removal method according to the present embodiment is applied to the site S where the skeleton T, which is an underground skeleton, is constructed has been described. However, the retaining wall removal method according to the present disclosure is not limited to the site S, and can be applied to various sites.

DESCRIPTION OF SYMBOLS 1, 11... Earth retaining wall 1b... Steel sheet pile 1c... Bottom part 1d... Leg part 1f... Connection part 2, 12... Formwork 2b... First surface 2c... Second surface 3... Supporting member 5, 5A, 15 Camber 5b, 15b Upper surface 5c, 15c Lower surface 5d First side surface 5f Second side surface 5g Inclined surface 5h Columnar portion 5j Inclined portion 6, 16... Hinge 10... Filler 15d... First side 15f... Second side B... Ground C... Space K... Layer K1... First side K2... Second side S... Site, T ... skeleton, T1 ... space, U ... ground surface, W ... interval, X ... building, Y ... backfill soil.

Claims (4)

A step of driving an earth retaining wall into the ground;
a step of excavating the ground located on one side of the earth retaining wall in plan view;
a step of constructing a skeleton in the space formed by the excavation;
filling a space between the earth retaining wall and the skeleton with a filler that hardens over time;
withdrawing the earth retaining wall from the ground before the filling material hardens;
comprising
How to remove retaining walls. After the step of constructing the skeleton, a step of installing a formwork between the earth retaining wall and the skeleton, and a step of backfilling between the formwork and the skeleton,
In the step of filling the filler, filling the gap between the retaining wall and the formwork with the filler after the step of backfilling;
Further comprising a step of pulling out the formwork from the ground after the step of filling the filler,
The earth retaining wall removal method according to claim 1. The step of installing the formwork includes a step of interposing a camber between the retaining wall and the formwork,
Withdrawing the formwork includes withdrawing the camber from the filler.
The earth retaining wall removal method according to claim 2. The camber is connected via a hinge to a surface of the formwork facing the retaining wall,
In the step of pulling out the camber, the camber is pulled out together with the formwork in a rotatable state via the hinge.
The earth retaining wall removal method according to claim 3.

Images